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critical design review
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Critical Design Review — Unter Critical Design Review oder abgekürzt CDR (deutsch: entscheidende Entwurfsprüfung) versteht man die letztgültige Planungskontrolle eines Projektes vor der Umsetzung. Es bildet einen wichtigen Meilenstein im Projektablauf, und ist oft auch… … Deutsch Wikipedia
Design review (US Government) — This page refers to the system engineering principle, for the magazine, see: Design Review (publication) In the United States military and NASA s engineering design life cycle, a phase of design reviews are held for technical and programmatic… … Wikipedia
Critical design — Critical Design, takes a critical theory based approach to design. Popularized by Anthony Dunne and Fiona Raby through their firm, Dunne Raby. Critical design uses designed artifacts as an embodied critique or commentary on consumer culture. Both … Wikipedia
Critical race theory — (CRT) is an academic discipline focused upon the intersection of race, law and power. Although no set of canonical doctrines or methodologies defines CRT, the movement is loosely unified by two common areas of inquiry. First, CRT has analyzed the … Wikipedia
Critical international relations theory — is a diverse set of schools of thought in International Relations (IR) that have criticized the theoretical, meta theoretical and/or political status quo, both in IR theory and in international politics more broadly from positivist as well as… … Wikipedia
Critical discourse analysis — (CDA) is an interdisciplinary approach to the study of discourse that views language as a form of social practice and focuses on the ways social and political domination are visible in text and talk.[1] Since Norman Fairclough s Language and… … Wikipedia
Critical legal studies — is a movement in legal thought that applied methods similar to those of critical theory (the Frankfurt School) to law. The abbreviations CLS and Crit are sometimes used to refer to the movement and its adherents. Contents 1 History 2 Themes 3… … Wikipedia
Critical pedagogy — Major works Pedagogy of the Oppressed … Wikipedia
Critical management studies — (CMS) is a loose but extensive grouping of politically left wing and theoretically informed critiques of management, business and organisation, grounded originally in a critical theory perspective. Today it encompasses a wide range of… … Wikipedia
Design management — is the business side of design. Design managers need to speak the language of the business and the language of design … Wikipedia
Critical psychology — Psychology … Wikipedia
critical design review
1 critical design review
2 critical design review
3 critical design review
4 Critical Design Review
5 critical design review
6 critical design review
7 critical design review
8 critical design review
9 critical design review
10 critical design software review
См. также в других словарях:
Critical Design Review — Unter Critical Design Review oder abgekürzt CDR (deutsch: entscheidende Entwurfsprüfung) versteht man die letztgültige Planungskontrolle eines Projektes vor der Umsetzung. Es bildet einen wichtigen Meilenstein im Projektablauf, und ist oft auch… … Deutsch Wikipedia
Design review (US Government) — This page refers to the system engineering principle, for the magazine, see: Design Review (publication) In the United States military and NASA s engineering design life cycle, a phase of design reviews are held for technical and programmatic… … Wikipedia
Critical design — Critical Design, takes a critical theory based approach to design. Popularized by Anthony Dunne and Fiona Raby through their firm, Dunne Raby. Critical design uses designed artifacts as an embodied critique or commentary on consumer culture. Both … Wikipedia
Critical race theory — (CRT) is an academic discipline focused upon the intersection of race, law and power. Although no set of canonical doctrines or methodologies defines CRT, the movement is loosely unified by two common areas of inquiry. First, CRT has analyzed the … Wikipedia
Critical international relations theory — is a diverse set of schools of thought in International Relations (IR) that have criticized the theoretical, meta theoretical and/or political status quo, both in IR theory and in international politics more broadly from positivist as well as… … Wikipedia
Critical discourse analysis — (CDA) is an interdisciplinary approach to the study of discourse that views language as a form of social practice and focuses on the ways social and political domination are visible in text and talk.[1] Since Norman Fairclough s Language and… … Wikipedia
Critical legal studies — is a movement in legal thought that applied methods similar to those of critical theory (the Frankfurt School) to law. The abbreviations CLS and Crit are sometimes used to refer to the movement and its adherents. Contents 1 History 2 Themes 3… … Wikipedia
Critical pedagogy — Major works Pedagogy of the Oppressed … Wikipedia
Critical management studies — (CMS) is a loose but extensive grouping of politically left wing and theoretically informed critiques of management, business and organisation, grounded originally in a critical theory perspective. Today it encompasses a wide range of… … Wikipedia
Design management — is the business side of design. Design managers need to speak the language of the business and the language of design … Wikipedia
Critical psychology — Psychology … Wikipedia
Critical Design Review
Critical design review: When engineering believes the design is ready to be “frozen” and also when a satisfactory prototype has met the qualification and other reliability tests, a final design review shall be scheduled.
Related terms:
Review
Critical design review
The Critical Design Review (CDR) closes the critical design phase of the project. A CDR presents the final designs through completed analyses, simulations, schematics, software code, and test results. It should present the engineering evaluation of the breadboard model of the project. A CDR must be held and signed off before design freeze and before any significant production begins. The design at CDR should be complete and comprehensive.
The design should be complete at CDR. The CDR should present all the same basic subjects as the PDR, but in final form. Here are some additional example items, beyond the items in a PDR, that a CDR might address:
Closure of action items, anomalies, deviations, waivers, and their resolution following the PDR
Design changes from the PDR
Final implementation plans including –
Engineering models, prototypes, flight units, and spares
Software design and process
Updated risk management plan –
Updated risk and hazard analysis
Qualification and environmental test plans
Integration and compliance plans
Status of procedures and verification plans
Test flow and history of the hardware
Completed support equipment and test jigs
Identification of residual risk items
Plans for distribution and support –
Warehousing and environmental control
Design
Nomenclature
computer aided design
conceive, design, implement, operate
critical design review
components off the shelf
Design Education Special Interest Group
design for assembly
Institution of Mechanical Engineers
International Organization for Standardization
multidisciplinary design optimization
product design specification
preliminary design review
substitute, combine, adapt, modify, put to use, erase, rearrange
system design review
Sharing Experience in Engineering Design
maximum deflection (m)
NASA space safety standards and procedures for human-rating requirements1
1.3 NASA Human Ratings Process
Of particular interest are the Human Rating requirements imposed by NASA on select systems. Many NASA systems require “Human Rating”. Systems requiring Human Rating must implement additional processes, procedures, and requirements necessary to produce human-rated space systems that protect the safety of crew members and passengers on NASA space missions.
Human-rated systems accommodate human needs, effectively utilize human capabilities, control hazards, and manage safety risk associated with human space flight, and provide, to the maximum extent practical, the capability to safely recover the crew from hazardous situations. Human rating is an integral part of all program activities throughout the life cycle of the system, including: design and development; test and verification; program management and control; flight readiness certification; mission operations; sustaining engineering; maintenance, upgrades, and disposal.
The Human-Rating Certification is granted to the crewed space system but the certification process and requirements affect functions and elements of other mission systems, such as control centers, launch pads, and communication systems. The types of crewed space systems that require a Human-Rating Certification include, but are not limited to, spacecraft and their launch vehicles, planetary bases and other planetary surface mobility systems that provide life support functions, and Extravehicular Activity (EVA) suits. A crewed space system consists of all the system elements that are occupied by the crew during the mission and provide life support functions for the crew. The crewed space system also includes all system elements that are physically attached to the crew-occupied element during the mission, while the crew is in the vehicle/system.
Verification of program compliance with the Human Ratings requirements is performed in conjunction with selected milestone reviews (System Requirements Review (SRR), System Definition Review (SDR), Preliminary Design Review (PDR), Critical Design Review (CDR), System Integration Review (SIR) and the Operational Readiness Review (ORR)) conducted in accordance with the requirements of NPR 7120.5, “NASA Space Flight Program and Project Management Requirements”, and NPR 7123.1, “NASA Systems Engineering Processes and Requirements”. NPR 8705.2, “Human-Rating Requirements for Space Systems”, specifies development of products that are reviewed at each of the selected milestone reviews. The adequacy of those products and the acceptability of progress toward Human-Rating Certification are used to verify compliance. In addition, the Human-Rating requirements and processes are subject to audit and assessment in accordance with the requirements contained within NPR 8705.6, “Safety and Mission Assurance Audits, Reviews, and Assessments”.
NPR 8705.2, “Human-Rating Requirements for Space Systems”, also defines and delineates specific responsibilities for Human Rating including overall authority assigned to the NASA Associate Administrator and assurance of implementation assigned to the Chief, Safety and Mission Assurance, and the NASA Chief Engineer as Technical Authorities within their realms of responsibility. Additional responsibilities and authorities are described as appropriate.
The Human-Rating Certification Process is linked to five major program milestones: System Requirements Review, System Definition Review, Preliminary Design Review, Critical Design Review, and Operational Readiness Review. The program’s compliance with the Human-Rating requirements and the contents of the Human-Rating Certification Package are endorsed and approved by all three Technical Authorities (Safety, Engineering, and Health and Medical) at each of the five milestones. Since it is not the intention of this article to restate the documented requirements and processes required for human rating, a summary of major certification elements from NPR 8705.2 is hereby provided:
The definition of reference missions for certification.
The incorporation of system capabilities to implement crew survival strategies for each phase of the reference missions.
The implementation of capabilities from the applicable technical requirements.
The utilization of safety analyses to influence system development and design.
The integration of the human into the system and human error management.
The verification, validation, and testing of critical system performance.
The flight test program and test objectives.
The system configuration management and related maintenance of the Human-Rating Certification.
Specific requirements, including specific technical requirements, are described in detail in Chapter 3 of NPR 8705.2 and are publicly available for review.
New applications for submarine cables
8.3.4.12 Design analysis
Design review and analysis for an underwater observatory can be a lengthy process that should be developed and communicated at the start of the project. Both preliminary and critical design reviews are likely to be necessary. In addition to review of the high-level system design, subsystem and component level design reviews are needed. Development of prototypes, testing and subsequent design revisions must be considered. Qualification and trial of wet and dry plant elements may be necessary. The use of interface control documents to define the responsibilities of suppliers and subcontractors is recommended.
Risks and Issues
Leveraging Other Events to Identify Risks throughout the Project
While risk-identification events are a smart way to begin a project, risks and issues come to light in many other functions of a project. Events where the design is critiqued such as critical design reviews and failure mode and effects analysis (FMEAs) often bring new risks and issues to light. Similarly, new risks may be identified at regular team meetings, customer and supplier visits, trips to trade fairs, and even hallway conversations. Risks can also come into focus when people are working alone, for example, reviewing competitive literature, studying patents or academic papers, reading component specifications, interpreting test results, or just working through a problem.
Delay sometimes reveals risks and issues. This delay can be detected with progress tracking such as the fever chart of Figure 5.17 or by missed milestones. Sometimes risks come to light through the four early warning signs of Section 5.3.6 : slower-than-expected progress, low quality work product, signs of faltering engagement, or concerns from others.
In all these cases, transactional leadership is important—develop and follow process to identify and record risks and issues. Then thoroughly track the root cause of all known failures whether at a customer site or from internal testing. But transformational leadership is also important: stay connected with the team, encourage open and honest discussion, and reward those who discover serious risks.
Introduction
3.5 Phase C
3.5.1 Objectives of phase C
The objectives of phase C are as follows:
Completion of the detailed definition of the system
Production and development testing of engineering models as required by the verification approach
Finalization of the AIV plan
3.5.2 Review at the end of phase C: Critical design review
At the end of phase C, a critical design review (CDR) is conducted with the following objectives:
Assess the qualification and validation status of the spacecraft and ground segment
Confirm compatibility with the identified external interfaces
Release the final design related to the spacecraft and ground segment
Release the final AIV plan
Release the verification control document. This document comprises the spacecraft and ground segment requirements and its state of verification
3.5.3 Documentation in phase C
| Phase | Meeting | Name | Document status |
|---|---|---|---|
| C | CDR | Project Organization Plan | Finalized |
| C | CDR | Mission Operation Concept Document | Updated |
| C | CDR | System Architecture Definition | Finalized |
| C | CDR | Spacecraft Technical Specification | Finalized |
| C | CDR | Ground Segment Technical Specification | Finalized |
| C | CDR | Budget Analysis | Finalized |
| C | CDR | AIV Plan and Procedures | Finalized |
| C | CDR | Verification Control Document | New |
| C | CDR | Frequency Request Acceptation | New |
| C | CDR | Mission Operation Procedures | New |
Reliability and Life Testing
CODES AND STANDARDS
Practically all military contracts contain clauses under quality assurance requiring reliability programs. This is becoming increasingly true in other fields as well, particularly civil aviation, nuclear power, and industries where equipment failure is potentially hazardous. Many contracts include provisions for a preliminary design review and also a critical design review before qualification tests. In addition, some contracts require a reliability demonstration test. Use is made in this latter case of all the engineering data that might be obtained in the qualification tests, if they precede the reliability demonstration test.
Table 7 presents a family tree of US Government documents establishing and supporting reliability requirements. New specifications are added frequently to build up the reliability factors and requirements. One area (not listed in the table) that is expanding steadily is special parts reliability specifications such as the MIL-R-38000 series. These specifications cover the acceptance and qualification testing of high-reliability parts.
Requirements Foundation
2.2.3.3 Requirements Rationale Traceability
The source information covered above does not tell why a requirement was included and this information can be very useful. The model built for source information can be easily expanded to account for rationale information. Simply add another column to the table titled “RATIONALE.” In this column you will include reasons why the requirement is included and/or the basis for the value identified.
We could simply include a separate paragraph in Section 6 for rationale along with its table. Or we can alter the earlier Section 6 paragraph and table as shown below for a hypothetical specification. In both of these tables it would be an improvement to include the paragraph title to convey more clearly what the requirement concerns without leafing back and forth through the document. The paragraph title was not included here in the interest of space.
Anyone who has tried to maintain information like this using a word processor (or, heaven forbid, a typewriter) knows it can be a little maddening. We will see later in the book that it can be made less so through a computer database approach. For now just think about the utility of this information and not how hard or easy it is to maintain.
Requirements source and rationale capture are examples of a phenomenon understood by many parents called delayed gratification. The value of the action taken today does not appear to match the near term cost but the value is greatly appreciated at some time in the future. The value of the money spent doing this work produces little immediate utility but many months or a few years later it can be very valuable to be able to recall the details of work accomplished earlier. As a result, it is sometimes difficult to justify to a program manager the expenditure of program funds to accomplish this work. Once a program manager experiences a serious program problem that has been solved by reference to this information, he or she will become a devotee of capturing it. For example, Col. Shaftly asks at a critical design review who the person was that came up with the idiotic idea to exclude a redundancy requirement. It can be helpful to your cause if not your popularity if you are able to reply with a smile, “I regret to inform you, Sir, that it was one Col. Shaftly, on June 13th two years ago at the preliminary design review.” Traceability is one of the requirements actions that contributes to the word “affordable” in the title of this book. It may not result in lower creation cost but has an effect on lowering life-cycle cost.
6.1.1.2 Requirements Source and Rationale
Table 6-1 identifies the source and rationale for each requirement in Sections 3, 5, and appendices except for titles-only paragraphs that are traceable only to the template employed.
| Para | Source | Rationale |
|---|---|---|
| 3.2.1.2 | Contracts letter 34-567 dated 11-10-90 | Customer-furnished equipment-driven |
| 3.2.1.3 | Customer system requirements review minutes | The kill radius was changed to 30 m |
| 3.2.1.4 | Derived from customer need as a function of our solution | Reaction time selected to account for best possible capability using a chemical rocket |
| 3.2.1.5 | Chief Engineer decision at ERB-1302 | Conflict between range and payload capacity resolved |
| 3.2.1.6 | System analysis memo ANAL-90-153 | Worst case impact angle is 13° |
Requirements Management
8.1.3.12 Development Data Package Concept
Once engineering drawings start coming off the boards or CAD stations, standard configuration management procedures are very effective in controlling the design baseline. Many organizations find it very difficult, however, to control the evolving requirements and concepts baseline and maintain decision traceability during the sometimes chaotic period leading up to the PDR. Many engineering organizations have found themselves in a sad predicament at a critical design review (CDR) without the backup data asked for by the customer for a critical decision made months earlier.
The requirements database concepts exposed in Chapter 9 can provide a means to capture not only program technical requirements but also rationale, sources, and traceability associated with these requirements. So, the database approach can be used to satisfy the need to retain rationale data for requirements but may not totally solve the design concept decision capture problem outside the requirements information component. We seek a solution that embraces both requirements and concept information and ways to manage the evolution of this information resource in early program phases.
Over a period of years, many system engineering organizations have evolved a universal view of all of the information of interest in the early phases of system development and defined a particular organizing structure for that information. One such concept, called a “development data package (DDP),” was advanced by logistics engineers at General Dynamics Space Systems Division in the early 1990s. Figure 8.9 illustrates one way this information package can be organized for a project. The horizontal matrix axis lists the sections of the DDP. The vertical matrix axis lists the organizations participating on an integrated product development team focused on developing a particular item that happened to be an avionics box.
The understanding is that there must be a place in the DDP for all members of the team to put all their information work product during the life cycle of the DDP. This includes the kinds of information that many organizations expect engineers to put in their engineering notebooks, journals, or logs. The DDP captures all information of interest to the team and makes it available to all team members. Later, we will see how computer technology can satisfy the availability requirement. First let us discuss DDP organization and life cycle.
Under this concept, each IPPT leader and principal engineer must create and maintain a DDP for his or her item beginning when the chief engineer authorized the team to start development work. The DDP provides a means to capture development information from all IPPT members in a common format between initiation of team activities and completion of the PDR. It must provide a place for every concurrent engineering team member in which to put his or her information product.
Between PDR and CDR, the content of the DDP should flow out to formal documentation destinations such as specifications, engineering drawings, and planning data libraries, and DDP maintenance should be discontinued as each section makes the transition. Table 8.5 defines the formal documentation destinations of each DDP section (noted in the vertical axis of Figure 8.9 ) subsequent to PDR. Generally, the team should be allowed the time between PDR and some time prior to CDR to complete the conversion between DDP content and the formal data destinations.
| DDP | Section Title | Formal Documentation Destination |
|---|---|---|
| A | Product entity | Specifications, specification tree, specialty engineering models |
| B | Interface | Specifications, engineering drawings |
| C | Development guidelines | Program planning, supplier SOWs |
| D | Dev planning | Program planning, supplier SOWs |
| E | Requirements | Specifications |
| F | Applicable documents | Specifications |
| G | Verification | Specifications, program test planning |
| H | Trade studies | Design rationale traceability documentation |
| I | Analyses | Design rationale traceability documentation |
| J | Development test | Integrated test plan |
| K | Design concept | Engineering drawings |
| L | Ops/logistic concept | Logistics support plan |
| M | Manufacturing concept | Manufacturing plan, facilitization |
| N | Tooling and STE concept | Procurement documents |
| O | Quality concept | Manufacturing planning documents |
| P | Material concept | Procurement documents |
| Q | Product qual testing | Integrated test plan, test procedures |
| R | Product acceptance testing | Integrated test plan, test procedures |
| S | System safety concept | System safety plan, hazard reporting |
| T | Cost compliance assurance | Program planning, specifications |
| U | Risk assessment | Design rationale documentation |
Where the program uses a computer database to capture item requirements, the DDP requirements section may simply reference the database content or be used as a baseline repository for the most recently approved snapshot of database content while the working database content continues to mature.
Whether word processing or database technology is employed, the team responsible for the particular DDP would apply a sound requirements analysis process, such as that covered in this book, to identify the content of the requirements set for the item.
The DDP could be assembled in paper media using typewriter or stand-alone computer technology, but the most powerful application of the concept requires networked microcomputers tied into the DDP located on a network server. The server is set up with a set of templates for each section that requires a specific application program, a drop box, and a working baseline consisting of all of the work completed to date.
At any time, anyone on the program may gain read-only access to anything in the working master. If the program is equipped with meeting room computer network access and video projection capability, periodic concurrent engineering team meetings may be accomplished by projecting directly from DDP resources. Periodically, even on a daily basis, an approved copy of the working master (complete or a subset) could be transferred to customer access. In fact, in early program phases, this would be a much more effective contract data requirement list (CDRL) item than the piles of reports commonly delivered to customer file cabinet resting places.
As useful as the DDP is in solving the information communication and integration problem during early program phases, the DDP concept is probably not the most efficient long-term solution to a company’s information needs except on a small project. But, given that a company does not now know what its aggregate system development information needs are or how those needs relate to long-term information needs, the DDP concept can provide a manageable growth path from ignorance to understanding. At the terminal end of this path, after applying the DDP concept on several programs, the company will have an excellent understanding of its needs and be able to phrase requirements for their information system builders on their route to a capability in model-driven development.
System safety and accident prevention
8.3.1.1 Phased and Integrated Safety Reviews
Safety reviews are carried out incrementally in phase with design and development activities. For such reason, they are called phased safety reviews. Safety reviews are often identified sequentially with 0, and Roman numerals I, II, III. Safety reviews are carried out either immediately before or after project reviews, depending on considerations of potential impact on design if some hazard controls are changed, rejected, or modified.
Phase 0 Safety Review is held during the conceptual phase of design. Phase I follows at the time of project Preliminary Design Review (PDR), then Phase II at the time of project Critical Design Review (CDR), and finally phase III at completion of successful verification of hazard controls implementation.
Safety data are the input to safety reviews. They consist of hazard reports and supporting data, becoming more and more detailed as project design and development activities progress.
At Phase 0, safety data are limited to the identification of hazards and applicable safety requirements. At Phase I, due to design evolution since the conceptual phase, new hazard reports may be presented for review while others may be canceled. The Phase I hazard reports will document all hazard causes while design and operational hazard controls are presented in a preliminary form. At phase II safety review, all details on design hazards controls and approved operational hazard controls are presented for review, together with hazard controls verification plans and procedures. Finally, at phase III safety review, the results of safety verification activities are presented.
Because new instruments and equipment are continuously sent to ISS and other are returned or disposed, every time the configuration of the space station changes, in particular in conjunction with departure and arrival of transport vehicles, a new cycle of integrated safety reviews is carried out.